Chemists have been working with organosilanes for decades, often seeking ways to improve the bond between inorganic and organic materials. Bis[3-(Triethoxysilyl) Propyl]Disulfide (TESPD) didn’t spring up out of nowhere. It started to gain traction once the rubber and tire industry began to chase better ways to reinforce materials. During the 1970s, research on tire compounds intensified, as companies pushed for lower rolling resistance and improved wet traction; silica became the filler of choice. Unfortunately, silica struggled to bond with rubber. That’s where compounds like TESPD changed the game by acting as coupling agents. Its history isn’t a footnote—advances in material science often hinge on improvements in these seemingly niche chemicals, and the shift in tire tech offers a classic example.
TESPD stands out because its molecular design brings together two reactive ends. The silicon component bonds well to glass, metals, and minerals, while the disulfide part links up with rubber chains. In plain speech, it glues together things that otherwise don’t mesh. This isn’t just a theory; industries have leaned heavily on TESPD to make products tougher, last longer, or simply perform in ways that older materials couldn’t manage. My own work in the rubber sector showed me firsthand how changing coupling agents can turn a mediocre compound into something fit for high-stress use. TESPD gave manufacturers reliability they could measure, whether for tires, adhesives, or coatings.
The molecule itself is a clear to light yellow liquid—some might say it looks unremarkable, but its chemistry argues otherwise. More than 90% pure by standard, it carries a distinct mercaptan odor. Its density sits in the range of 1.07 grams per cubic centimeter at 25°C. You’ll see it classified with a boiling point above 150°C under reduced pressure. Moisture must stay away from TESPD, as water kicks off hydrolysis, producing ethanol and forming silanols. In the lab, even a little slip in handling can spoil the batch. It dissolves in typical organic solvents like benzene and toluene. Of course, anyone who’s handled TESPD knows that the real world has little patience for wishful thinking—careful control of moisture matters far more than textbook properties suggest.
Suppliers put out TESPD with strict technical specs, not just for consistency but to sidestep problems later in the process chain. Labels will list purity, sometimes as “active ingredient content,” and break down the percentage of silane and sulfur content. For shipping, you’ll find it under UN 1993 (flammable liquid, n.o.s.), generally packed in steel drums or large totes, and every label ought to include GHS hazard statements. My advice: don’t skip the safety data sheets, since GHS symbols barely hint at the practical hazards during handling. You can see why labeling goes past bureaucracy in this case.
Manufacturers synthesize TESPD in a two-step process. First, alkoxysilane reacts with an organosulfur compound—a classic example uses triethoxysilane and 3-chloropropyltrimethoxysilane—under basic conditions to produce the dual silane-disulfide structure. Controlling reaction temperature and moisture during synthesis holds the key to decent yields. Even small process drift can affect downstream usability, as I’ve seen in production environments where slow hydrolysis or improper mixing led to hours of lost time. Efficient distillation and purification round out the process before packing up the product.
Once in use, TESPD participates in several reactions: its ethoxysilyl groups bond to silanol-rich surfaces via hydrolysis and condensation, while the disulfide bridge breaks to form covalent links with sulfur-cured rubber chains under vulcanization. Some R&D groups tweak the alkoxy groups (switching ethoxy for methoxy) to modify reactivity or compatibility with different fillers. The disulfide bond itself allows for chemical tailoring. I’ve worked with teams modifying TESPD for specialty rubber applications, and the difference in crack resistance and strength can be dramatic just by small backbone adjustments.
This compound shows up under several industrial monikers. You’ll find Bis[3-(Triethoxysilyl) Propyl]Disulfide also named as TESPD, Si-69, and sometimes as Disulfane silane. It’s easy to get lost in the chemical jargon, especially when regulatory or procurement documents use different names. Cross-checking synonyms isn’t a nitpicky detail—it prevents costly order errors in high-volume operations, as anyone who’s received the wrong grade knows.
Working with TESPD requires gloves, goggles, and local exhaust ventilation—no exceptions. Liquid splashes can burn, and vapors can irritate eyes and lungs. In my time supervising a prep line at a custom compounding plant, I saw emergency showers and eyewash stations earn their keep during TESPD mishaps. Proper training trumps protocol checklists; reading the Globally Harmonized System (GHS) codes helps, but experience teaches respect for reactivity. Spills demand immediate cleanup with absorbents, and waste streams need thoughtful segregation to keep halogenated and non-halogenated chemicals apart. Ignoring material compatibility or storage times leads straight to unnecessary risk.
TESPD’s primary claim to fame sits in the tire industry, where it’s used to improve the linkage between silica fillers and rubber. Fuel efficiency gains and better grip on wet roads aren’t just marketing noise—studies back up these benefits. The world also sees TESPD pop up in silane-modified adhesives, sealants, and coatings, as it eases the stubborn problem of sticking dissimilar materials together. Having solved practical problems with TESPD-modified rubber compounds myself, I can say it’s not hype: switching out traditional coupling agents slashed customer complaints and delivered more consistent performance.
Research on TESPD stretches from polymer chemistry fundamentals to automotive engineering. Scientists keep probing new silane backbone tweaks in search of yet tougher tires and more durable building materials. Green chemistry efforts investigate whether bio-based alternatives or improved reaction conditions can lower environmental impacts. In more than one lab project, innovation sometimes meant circling right back to basics—reviewing hydrolysis kinetics or exploring unexpected interaction with new fillers. Collaboration between R&D teams and end-users consistently pushes TesPD’s applications and encourages open sharing of operational insights.
Toxicologists have run both acute and chronic exposure studies on TESPD. Skin and eye irritation rank as main risks—those aren’t theoretical; operators with splashed skin report stinging and redness. Inhalation studies in animals flagged some respiratory tract effects at high concentration, although routine production levels typically stay well below danger zones if controls work as planned. In the past decade, regulatory frameworks call for regular review of exposure limits, with industry-funded studies expanding the dataset. Experience in safety committees showed me that real-life incidents often drive stricter standards quicker than scientific publications. Keeping tight air monitoring and personal hygiene procedures goes a long way toward minimizing health worries.
The future for TESPD likely lies beyond rubber and tires, branching into composite construction, electronics, and renewable energy modules. Companies have started to chase finer tuning of mechanical and thermal properties with advanced hybrid fillers, and these developments depend on better surface coupling chemistry. Sustainable production, microplastics impact, and recyclability could all influence use patterns. As climate change worries move center stage, any material that enables lighter, tougher, and longer-lasting sustainable goods should see rising demand. My own prediction: TESPD, or its next-gen cousins, will figure in a surprising range of new products, from smarter building panels to bio-derived elastomers. Industry and research need to keep collaborating tightly, since small advances ripple out far beyond the factory floor.
Long chemical names sometimes make people tune out. Bis[3-(Triethoxysilyl) Propyl]Disulfide might fall into that category at first glance, yet the work it does keeps a lot of everyday items running smoothly. This compound builds bridges between two worlds that normally don’t want to mix: rubber and silica. Without this link, car tires don't grip the road as reliably, and coatings on parts wear away quicker.
Imagine a tire made mainly from natural or synthetic rubber. Rubber alone costs less and stretches well, but toss in some silica to get more mileage and better fuel economy, and the materials start to repel each other. Bis[3-(Triethoxysilyl) Propyl]Disulfide steps in as a professional matchmaker. On one end, it has a group that bonds tightly with rubber. On the other, the silane groups grab onto silica. The result: tires keep their flexibility, but also pick up better wear resistance, improved traction in the rain, and a gentle bump in fuel savings. Manufacturers credit these types of silane coupling agents, this one especially, for moves toward “green tire” technology—balancing performance with sustainability.
Rubber processing isn’t the only place this compound pulls its weight. In sealants, adhesives, paints, and protective coatings, the same principles apply. Imagine machinery in a dusty or damp environment. Treatment with this silane compound creates stronger bonds between metal, glass, fillers, or fiberglass and coatings meant to protect these surfaces from corrosion. Bridges, tunnels, pipelines, and industrial machines say thanks each time they avoid an early retirement caused by rust or delamination.
There’s another plus that becomes big news in an industry responsible for plenty of emissions. By holding rubber and silica together, bis[3-(triethoxysilyl) propyl]disulfide lets factories skip some old chemical additives. This helps drop the amount of volatile organic compounds (VOCs) released, which means cleaner air and healthier workers. It’s not just theory: researchers digging into tire manufacturing report measurable VOC reductions after switching to this class of silanes.
The magic works at the molecular level, but the idea stays simple. Two materials that want nothing to do with each other can learn to get along if someone introduces a little chemistry. The “disulfide” part of the name is more than a mouthful—it’s an ingredient that lets it react and “cure” into big rubber molecules during the vulcanization step (the one that turns sticky rubber into something strong enough for tires). It’s this reliable trick that turned silane coupling agents like this one into an industrial staple.
Every solution brings a new challenge. Bis[3-(Triethoxysilyl) Propyl]Disulfide carries some health and environmental risks if handled carelessly. Companies handling tons of powder and liquids can’t skip proper ventilation, training, and disposal methods. The chemistry rewards safety, and regulators want to make sure the march for better, greener tires doesn’t end up hurting people or soil and water down the line.
Specialty chemistry sometimes looks mysterious from the outside, but anyone who has driven in the rain or used a strong adhesive has already put trust in this type of compound. Keeping up with good science means keeping an eye on both the benefits and the long game for safety.
Most people rarely think about chemicals beyond household cleaners and the gasoline pump. For me, a summer working in a university research lab opened my eyes to what safety for hazardous chemicals actually means. The rules and routines have a purpose—one slip, and you're not just losing an experiment; you can really get hurt or cause harm to others.
Before working with any chemical, I always review the Safety Data Sheet. I’m talking details: toxicity, flammability, and what to do if it gets on your skin or in your eyes. No one expects to be splashed, but memory matters in moments when you freeze. Keeping a hard copy close by and a summary taped inside a drawer once saved my skin during a hurried mix-up.
Goggles, gloves, and lab coats sound basic, but they carry real weight in safety. I learned early that regular latex gloves don’t stand up to solvents like acetone or strong acids. Nitrile gloves handle more, but specialty gloves work best for the harshest stuff. One day, a chemical-resistant apron shielded me from a splash that would have burned straight through a T-shirt. Shoes with closed toes aren’t just a dress code. They keep your feet safe if a beaker tips.
Stretching for supplies after pouring a hazardous liquid feels clumsy and risky. I lay out what I’ll need—pipettes, gauze, proper containers—so nothing has to be grabbed last minute. I also familiarize myself with the nearest eyewash station and shower in every building I visit. Fast access shaves away panic during an accident.
Plenty of chemicals need a fume hood. I learned quickly that “just opening a window” didn’t cut it once acrid vapors hit my nose. A fume hood or a proper ventilated area keeps fumes out of your lungs and away from sparks or hot plates. Sealing containers tightly and labeling everything clearly prevents confusion and cross-contamination. Anything leftover finds its way into a properly labeled disposal container. I never pour anything down the sink because it’s illegal and dangerous for the environment.
There’s a reason senior chemists push for the buddy system. If something goes wrong, there’s someone who can run for help or call emergency services. Distractions — phones, music, and chatting — make people forget small things like capping bottles or washing hands. In my time working with reactive materials, group awareness was the strongest shield against small mistakes turning big.
Strong training stands out above everything else. Regular drills keep reflexes sharp. Management in labs or factories should provide frequent refresher courses. I’ve seen mentorship work well: seasoned employees guiding new hires through each step, not just tossing a manual at them.
Investing in good ventilation gear and quality PPE costs more upfront but saves lives and money in the long run. Encouraging a culture where people can speak up if something feels off creates a safer space. No chemical is “harmless” until proven otherwise.
Over time, safety habits stick. Caring about the people around you and your own skin means respecting every chemical on the list. Information, preparation, and teamwork carry more weight than any shortcut. These are lessons that don’t just apply to the lab, but anywhere risky substances show up.
Every time someone deals with silane coupling agents, risks sneak in quietly. Bis[3-(Triethoxysilyl) Propyl]Disulfide doesn’t forgive mistakes. A few years back, I saw what a small spill in an unventilated storeroom did to paint on the shelves and the lungs of a coworker. This stuff is easy to underestimate—I learned that firsthand.
Keeping this chemical dry takes precedence over everything else. Moisture in the air causes hydrolysis, which means new compounds develop quietly and ruin what you bought. The chemical’s disulfide bond likes stability, not wild swings in humidity or damp corners. Sealing the container tight, away from wash areas and pipes, keeps it in working order. I’ve seen product break down from a leaky lid alone—money and safety both gone because moisture snuck past a rubber ring.
Storing it cool, below 30°C, stops the chemical from cooking itself. Back in university, my lab partner once ignored temperature guidance, loaded a container in a supply closet near the furnace, and days later, fumes filled the space. It set off alarms and brought in the fire marshal. Heat speeds up side reactions, and nasty byproducts threaten anyone working nearby. I keep mine in a refrigerator labeled for chemicals—no food, no drinks, no confusion. The fewer surprises in that bottle, the better.
UV rays break chemical bonds. Direct sunlight, even from a window, turns this liquid yellow as the disulfide splits and new smelly fragments form. I store everything in amber bottles or opaque drums, stacked inside cabinets lined with plastic, never near glass doors. There's no faster way to ruin your inventory than ignoring this.
You get one sniff of the fumes before you decide to air out the space. My first warehouse gig taught me to never underestimate chemical volatility. This substance gives off vapors that corrode metal fittings, short out wiring, and build up enough to spark headaches and eye irritation. Good airflow, either through a fume hood or dedicated local exhaust, stops these vapors from hanging around.
Mixing oxidizers, acids, or strong alkalis with silane compounds invites reactions that belong in textbooks, not storerooms. I store silane-based materials far from cleaning chemicals, bleach, or even random metal parts. One forgotten rag with a mystery stain can start a reaction nobody wants. Some folks keep a spreadsheet of all chemicals and their risks—mine is taped to the inside cabinet door, updated every time a new drum arrives.
Labeling ensures nobody grabs the wrong bottle or forgets what sits behind a faded sticker. I use weatherproof labels, double-check the hazard icons, and jot down the arrival date and batch number. That way, expired materials never get missed or buried under new stock. I lost count of times a rushed worker grabbed the oldest bottle and dealt with a mess because the label peeled off. Proper labeling cuts accidents and replacement costs.
Keen awareness and routine checks make safe storage of Bis[3-(Triethoxysilyl) Propyl]Disulfide a habit, not a checkbox. This chemical rewards respect and punishes shortcuts—and anyone who’s dealt with a near-miss or cleanup knows shortcuts never pay off. Sharing those experiences, instead of hiding mistakes, prevents the next accident down the line.
Knowing the chemical structure and formula of a product is not just about pure science. It matters every day—on a factory floor, in a research lab, or even at home with household cleaners. If you’ve ever read a label and wondered what makes up the stuff inside, you’re not alone. The structure and formula give the blueprint. They reveal what a product is really made of, which helps people guard against potential hazards and make smart choices.
The chemical structure shows how atoms connect. Think of it like a map. Carbon, hydrogen, oxygen, nitrogen—they line up in patterns, each bond pointing in a direction. This map tells people how a molecule behaves. The formula, on the other hand, counts up the atoms: C2H6O tells you there are two carbons, six hydrogens, and one oxygen. But that same formula can point to more than one structure—ethanol or dimethyl ether. With chemistry, the map and the count work together.
Health and safety ride on clear chemical formulas. Take cleaning products. If you know a bottle contains sodium hypochlorite (NaOCl), you know it’s bleach. Houses, restaurants, and hospitals rely on these facts each day. Safety manuals and first responders depend on the details to stop harm quickly. Without a clear structure and formula, even experienced technicians can stumble.
Back in college, I remember a lab incident with ethylene glycol. Both ethylene glycol and methanol show up as clear, sweet-tasting liquids with very close formulas. Only one is dangerously toxic in small amounts—that difference in atomic arrangement is everything. Quick identification came from checking both the count and the bonds on a sheet. That little piece of paper made the difference between a close call and a disaster.
Regulations demand formula transparency for a reason. The EU’s REACH program and the U.S. Environmental Protection Agency both require accurate listings. Hidden ingredients led to public health issues far too often—think asbestos and lead paint scandals. By law, companies now reveal what’s really inside, down to the last atom for many substances.
People deserve that kind of openness. Whether thinking about allergies, pollution, farming, or school safety, chemical structure and formulas form the ground truth. Anyone should be able to search a public database and cross-check a label. Online tools like PubChem make this possible for almost anyone with an internet connection. You get a picture, a formula, even hazard statements. Knowledge gets democratized.
More people now push for QR codes on product labels—scan and see not just a formula, but safety measures, disposal guidelines, and more. Schools introduce basic molecular structure lessons early, showing kids how to look beyond fancy brand claims. Fact sheets in simple language—no jargon, just diagrams and numbers—help families spot risks without needing a science degree.
Better awareness of structure and formula doesn’t just help in emergencies. It builds trust between companies and the public. When people know what they’re working with, choices become smarter, safer, and more sustainable. Every barcode, every chemical name, every label can be a window into the science that keeps us healthy and informed.
In labs and at factory floors, people blend Bis[3-(Triethoxysilyl) Propyl]Disulfide, usually called TESPD or Si69, with other silanes to tweak rubber or composite properties. This compound gets tossed into many rubber compounding recipes, especially in the tire industry, to link silica to the rubber backbone. The action depends on its twin nature—sulfur in the middle, silane ends waving on both sides. But chemistry isn’t just plug-and-play. Putting two or more silane coupling agents in the same barrel can get unpredictable.
From firsthand experience in rubber compounding, mixing Si69 with silanes like Vinyltrimethoxysilane or APTES brings both risk and reward. Silanes react with fillers like silica and, at the same time, with the polymer through their other “tail.” If two coupling agents have reactive groups competing for the same surface sites, they trip over each other. Water in the air or stray catalysts—think acids or bases left unwashed—can set off premature hydrolysis. You wind up with clumped fillers or side reactions that lock before you even start mixing with rubber. With something as fussy as silica, getting just the right proportion and pre-mixing sequence sometimes calls for trial, error, and patience.
I’ve seen chemists swap out a chunk of Si69 for something like n-Propyltrimethoxysilane to cut rolling resistance in tires while keeping the same processing window. Still, load up too much and the rubber network suffers, showing poor wear or inconsistent curing. There’s a limit to how much blending and swapping brings improvements; tails on different molecules bring new functionality, but also new pitfalls—bridging to the rubber phase, making the mix more sensitive to scorch, or causing release problems on the mold.
Trying to boost silica bonding by pouring in various silanes only works if their chemistries line up. TESPD’s disulfide link does one job: providing sulfur for vulcanization. Pairing TESPD with amino- or epoxy-silanes can overload certain reactions in the vulcanization stage, stalling cure speed or affecting crosslink density. Commercial tire makers run batch trials under carefully controlled mixing and curing because a blend that looks fine in the lab may split apart across kilometers of factory floor.
Some combinations, like Si69 with methyl- or vinyl-silanes, occasionally work together by spreading functionality across the rubber-filler boundary. Yet, too much “help” from different silanes can eat up available sites on silica, leading to no real improvement—or even a drop in performance.
Open conversations with suppliers pay off when you want to tweak the coupling agent combo. Field-testing on a pilot line beats relying only on datasheets or sales decks. Some chemists use a silane “primer” on the filler first, letting it anchor before adding the rubber and a second agent. Others keep to single-silane approaches and push for more precise mixing temperatures, shorter pre-mix times, or adjust pH to minimize side reactions.
I’ve seen clear wins with blending, but only after controlled trials—testing wear, cure rate, and dynamic properties for weeks. There’s rarely a free lunch. Compatibility often depends on patience, transparency with partners, and a readiness to tweak recipes batch by batch. Trust the data, listen to your operators, and adjust one variable at a time. Mixing silane coupling agents can unlock fresh performance but only if the factory floor stays part of the conversation.
![Bis[3-(Triethoxysilyl) Propyl]Disulfide](/static/26ffdaf2-b05a-4718-b9a8-e71fecc06434/images/2d/bis-3-triethoxysilyl-propyl-disulfide.png)
![Bis[3-(Triethoxysilyl) Propyl]Disulfide](/static/26ffdaf2-b05a-4718-b9a8-e71fecc06434/images/3d/bis-3-triethoxysilyl-propyl-disulfide.gif)
| Names | |
| Preferred IUPAC name | bis[3-(triethoxysilyl)propyl] disulfide |
| Other names |
TESPD Bis[3-(triethoxysilyl)propyl]disulfane Bis(3-(triethoxysilyl)propyl)disulfide |
| Pronunciation | /ˈbɪs θriː traɪˌɛθɒk.siˈsaɪl.i ˈprəʊpɪl daɪˈsʌlfaɪd/ |
| Identifiers | |
| CAS Number | 40372-72-3 |
| Beilstein Reference | 3588734 |
| ChEBI | CHEBI:82458 |
| ChEMBL | CHEMBL514402 |
| ChemSpider | 14909 |
| DrugBank | DB16663 |
| ECHA InfoCard | 07e1b8ba-899e-4d81-bf8c-91ff25a6e770 |
| EC Number | 612-108-00-0 |
| Gmelin Reference | 131025 |
| KEGG | C11246 |
| MeSH | D003703 |
| PubChem CID | 24871459 |
| RTECS number | VV5775000 |
| UNII | F9L4QN7JCU |
| UN number | UN3334 |
| CompTox Dashboard (EPA) | DTXSID7025044 |
| Properties | |
| Chemical formula | C18H42O6S2Si2 |
| Molar mass | 538.9 g/mol |
| Appearance | Light yellow transparent liquid |
| Odor | Characteristic |
| Density | 1.08 g/mL at 25 °C (lit.) |
| Solubility in water | Insoluble in water |
| log P | 4.6 |
| Vapor pressure | <0.01 mmHg (20°C) |
| Acidity (pKa) | 9.2 |
| Basicity (pKb) | 1.5 |
| Magnetic susceptibility (χ) | -79.31×10⁻⁶ cm³/mol |
| Refractive index (nD) | 1.480 |
| Viscosity | “3-5 mPa·s (25°C)” |
| Dipole moment | 2.05 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 817.8 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -1265.9 kJ/mol |
| Pharmacology | |
| ATC code | Not assigned |
| Hazards | |
| Main hazards | Harmful if swallowed. Causes serious eye irritation. Causes skin irritation. May cause an allergic skin reaction. |
| GHS labelling | GHS07, GHS08 |
| Pictograms | GHS06, GHS07, GHS08 |
| Signal word | Danger |
| Hazard statements | Harmful if swallowed. Causes serious eye irritation. Causes skin irritation. May cause an allergic skin reaction. |
| Precautionary statements | Precautionary statements of Bis[3-(Triethoxysilyl) Propyl]Disulfide: "P261, P264, P271, P272, P273, P280, P302+P352, P321, P333+P313, P362+P364, P501 |
| NFPA 704 (fire diamond) | 2-1-0 |
| Flash point | 180 °C |
| Autoignition temperature | 259 °C (498 °F; 532 K) |
| Lethal dose or concentration | LD50 Oral Rat: >2000 mg/kg |
| LD50 (median dose) | LD50 (median dose): Oral, Rat: 6930 mg/kg |
| PEL (Permissible) | PEL (Permissible Exposure Limit) for Bis[3-(Triethoxysilyl) Propyl]Disulfide: Not established |
| REL (Recommended) | 1 mg/ml in ethanol |
| Related compounds | |
| Related compounds |
Bis[3-(trimethoxysilyl)propyl]disulfide 3-Mercaptopropyltriethoxysilane 3-Aminopropyltriethoxysilane 3-Glycidoxypropyltriethoxysilane Triethoxysilane |
